Thermal aberration analysis in Nd:YVO4

authored by: Merle Schneewind, Phillip Booker, Stefan Spiekermann, Peter Weßels, Jörg Neumann, Dietmar Kracht
Abstract: Laser sources for future gravitational wave detectors (GWDs) must meet demanding requirements including single-frequency output powers of above 700 W at 1064 nm, low noise and linear polarization with high beam quality and low higher-order mode content. Nd:YVO4 is an excellent material to the amplify the output of a low power seed, as 195 W output power at 1064 nm with low noise and linear polarization have already been demonstrated in multi-stage Nd:YVO4 amplification. However, further power scaling was limited because of higher-order modes originating from aberrated thermal lensing. In this work, the aberrations of the thermal lens in Nd:YVO4 were analyzed in a single-stage amplifier configuration. The crystal was seeded and pumped at 1064 nm and 878.6 nm, respectively, while probing the thermal lens with a beam at 976 nm. The wavefront of this probe beam was analyzed with a Shack-Hartmann sensor. The amplifier was characterized up to 43 W output power with 46 % extraction efficiency. We report a wavefront analysis with major contributions from defocus, astigmatism, and spherical aberration. The experimental results were complemented by an in-house developed numerical thermo-optical simulation model that, for the first time, included the major temperature-dependencies, i.e., of the emission cross-sections, thermal conductivity, thermal expansion, and heat capacity. We achieved excellent agreement of both output power and aberrations between simulations and experiment. Moreover, we introduced measures to compensate the aberrations in Nd:YVO4 leading the path to full compatibility with the demanded GWD requirements.
Organisation(s): QuantumFrontiers
External Organisation(s): Laser Zentrum Hannover e.V. (LZH)
Type: Conference contribution
No. of pages: 3
Publication date: 12.03.2024
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Condensed Matter Physics, Computer Science Applications, Applied Mathematics, Electrical and Electronic Engineering
Electronic version(s): https://doi.org/10.1117/12.3002325 (Access: Closed)

BibTeX

@inproceedings{74747ffac4324ccc9a7e9ef8df1e2311,
title = "Thermal aberration analysis in Nd:YVO4",
abstract = "Laser sources for future gravitational wave detectors (GWDs) must meet demanding requirements including single-frequency output powers of above 700 W at 1064 nm, low noise and linear polarization with high beam quality and low higher-order mode content. Nd:YVO4 is an excellent material to the amplify the output of a low power seed, as 195 W output power at 1064 nm with low noise and linear polarization have already been demonstrated in multi-stage Nd:YVO4 amplification. However, further power scaling was limited because of higher-order modes originating from aberrated thermal lensing. In this work, the aberrations of the thermal lens in Nd:YVO4 were analyzed in a single-stage amplifier configuration. The crystal was seeded and pumped at 1064 nm and 878.6 nm, respectively, while probing the thermal lens with a beam at 976 nm. The wavefront of this probe beam was analyzed with a Shack-Hartmann sensor. The amplifier was characterized up to 43 W output power with 46 % extraction efficiency. We report a wavefront analysis with major contributions from defocus, astigmatism, and spherical aberration. The experimental results were complemented by an in-house developed numerical thermo-optical simulation model that, for the first time, included the major temperature-dependencies, i.e., of the emission cross-sections, thermal conductivity, thermal expansion, and heat capacity. We achieved excellent agreement of both output power and aberrations between simulations and experiment. Moreover, we introduced measures to compensate the aberrations in Nd:YVO4 leading the path to full compatibility with the demanded GWD requirements.",
keywords = "gravitational wave detector lasers, Nd:YVO4 amplifier, thermal aberrations",
author = "Merle Schneewind and Phillip Booker and Stefan Spiekermann and Peter We{\ss}els and J{\"o}rg Neumann and Dietmar Kracht",
note = "Funding Information: Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany\u2019s Excellence Strategy \u2013 EXC-2123 QuantumFrontiers \u2013 390837967. ; Solid State Lasers XXXIII: Technology and Devices 2024 ; Conference date: 28-01-2024 Through 29-01-2024",
year = "2024",
month = mar,
day = "12",
doi = "10.1117/12.3002325",
language = "English",
series = "Proceedings of SPIE - The International Society for Optical Engineering",
publisher = "SPIE",
editor = "Clarkson, {W. Andrew} and Shori, {Ramesh K.}",
booktitle = "Solid State Lasers XXXIII",
address = "United States",
}